Electrolytic refining of metals



Patented Nov. 23, 1926.

FRANK r. COLOUR-1D, on NEW YORK, N. Y.,

ASSIGNOR TO UNITED STATES SMELTING,

REFINING & MINING COMPANY, OF PORTLAND, MAINE, A CORPORATION OF MAINE.

ELECTROLYTIC BEFINING OF METALS.

No Drawing.

The invention relates to the electrodeposition of metals, and more particularly to the electrodeposition of zinc. It is the practice in the electrodeposition of zinc to use. socalled addition reagents in the electrolyte, and the present invention is based on the discovery of new reagents of this character 1 which may be used with marked advantage over prior reagents in the electrodeposition of zinc." The presence of addition reagents quiets the gasy action at both the anodes and g phuric acid per liter. The common addition the cathodes, and also tends to make the cathode deposit less crystalline. The proper amount to. use depends upon the chemical composition, the temperature, and the rate of circulation of the electrolyte, and the current density and the amount and character of the impurities in the electrolyte.

The new reagents are classified as water soluble hydroxy derivatives of benzol (or benzene), which includes the sulfonic acids of phenol, cresoland toluol. Oresol is an example of this class of water soluble hydroxy derivatives of benzol which may be used as an addition reagent with especially goods results, but it will be understood that except as limited by the terms of the claims the invention also includes the use of the other derivatives.

I have discovered that a water soluble hydroxy derivative of benzol, such'forinstance, as cresol may be used as an addition reagent in certain electrolytes with remarkably, advantageous results. It may be used to replace many of the addition reagents commonly used and because of its comparatively low price, a substantial economy may be efiected. It may-be used alone or in partial replacement of some of the commonly used addition reagents, eflecting not only an economy thereby, but permitting a substitution to take place in old electrolyte, thus avoiding the cost of new electrolyte when changing over to the new addition reagent. In many,

cases it produces a cathode deposit superior to deposits obtained from other addition reagents, increasing thereby the etliciency of the operation and resulting in an important economy in the power consumption. No ac.- cumulation in the electrolyte of substances which might finally cause the electrolyte to form non-adherent and crystalline deposits has been noticed with this additionreagent as in the case with-some of the prior addition reagents commonlyuscd.

will depend upon varying conditions.

Application filed January 2, 1926. Serial No. 19,010.

The use of this addition reagent has given particularly excellent results 1n the electrodeposition of zinc with a sulphuric acid electrolyte. While the composition of the electrolyte can vary considerably without I materially affecting the character of the deposit, excellent results? have, been obtained with an electrolyte which at the start contained rams of zinc, as zinc sulphate, per liter, and which at the end contained 30 rams of zinc, and 100 grams of free sulreagent in the electrodeposition of zinc has v tual practice, this addition reagent when used alone, is added daily to the electrolyte in the form of a solution of the cresol in a portion of the electrolyte at the rate of one to two pounds of the cresol per ton of zinc roduced; while if used in conjunction with glue, the total quantity of the two reagents added daily is one to two pounds per ton of zinc produced, with the glue and the new reagent varying in such proportion as desired. Cresol together with sulphite li gnose may be used as addition reagents in the electrodeposition of zinc with sulphuric acid electrolytes. The proportions of the two reagents sol together with sulphite lignose and glue may be used as addition reagents in the electrodeposition of zinc with sulphuric acid electrolytes. The proportion of these addition reagents may vary according to. conditions. The new addition reagent alone or in conjunction with otheraddition reagents produces bright and dense deposits of zinc with sulphuric acid electrolytes.

What is claimed is:

1. That improvement in the electrodeposition of zinc with sulphuric acid elec rolytes which consists in the use in the acid electrolyte of water soluble hydroxy derivatives of benzol as addition reagents.

2. That improvementi the electrodeposi- .tion of zinc with sulphuric acid electrolytes which consists in the use in the acid electrolyte of cresol as an addition reagent.

3. That improvement in the electrodeposition of zinc with sulphuric acid electrolytes which consists in the use as an addition rewith other addition reagents.

. 4. That improvement in the electrodeposition of zinc with sulphuric acid electrolytes which consists in the use as an addition 1'e agent in the acid electrolyte, of water soluble .hydroxy derivatives of benzol in conjunction with sulphite lignose.

5. That improvement in the electrodeposition of zinc with sulphuric acid electrolytes which consists in the use as an addition reagent in the acid electrolyte, of water solub ehydroxy derivatives of benzol, in conjunction with sulphite lignose and glue.

6. That improvement in the electrodeposition of zinc with sulphuric acid electrolytes which consists in the useas an addition reagent in the acid electrolyte, of cresol in conjunction wiih sulphite lignose.

7 That improvement in the electrodeposition of zinc with sulphuric acid electrolytes which consists in the use as an addition reagent in the acid electrolyte, of cresol in conjunction With sulphite lignose and glue.

In testimony whereof I have signed my name to this specification.

FRANK F. COLCORD. 

